Parameter not included when using swift style commenting with obj-c

While compiling obj-c using swift doc headers, while other keywords work, eg: - returns:, - see: etc. Parameters will only appear using the @param syntax.

Does not appear

- parameter str:   The string to repeat.

Appears as a bullet point, including param

- param str:   The string to repeat.

Appears as a parameter

@param  The string to repeat.

Does not appear

- parameter str:   The string to repeat.
- see: nothing

Appears as standard text above the see callout

- param str:   The string to repeat.
- see: nothing

Appears as a bullet point

- param str:   The string to repeat.
- returns: nothing

So the parameter keyword is being parsed, but not being outputted in the documentation,